In this study, we are investigating the effect of preadsorbed fibrinogen (Fg) and fibronectin (Fn) on monocyte and macrophage adhesion to surfaces, and cytokine secretion from the adsorbed biomolecules. The adhesion studies are done on modified 96-well polystyrene microtiter plates made of untreated polystyrene (PS), oxygenated tissue culture polystyrene (TCPS), and other commercially available plates. The surface of the plates is analyzed with ESCA. Results to date indicate that 1) monocyte adhesion and TNF( release are affected by surface chemistry and pre-adsorbed proteins, 2) the amount of TNF( released is not directly proportional to the number of adherent cells, and 3) adsorbed fibrinogen promotes the release of TNF(..